This invention relates generally to pipe wrap machines and more particularly concerns machines for wrapping pipe stored on a reel.
In typical installations of underground pipe or tubing systems, the present practice involves either off-site or on-site procedures to wrap the pipe with one or more layers of protective material. In the off-site procedure, the pipe is wrapped in straight lengths of twenty, forty or sixty feet before shipment to the site. This is generally accomplished by moving straight lengths of pipe through a fixed position pipe wrap machine. After the wrapped pipe is delivered to the site, the pipe joints are welded and the welded joints are wrapped to complete wrapping of the entire length of pipe. The separate joint welds and wraps are at best inefficient and at worst result in inconsistent and welding along the total pipe length. In the on-site application, the pipe is laid and welded and then wrapped by a pipe wrap machine which travels along the pipe. The manipulation and operation of the pipe wrap machine along thousands of feet of pipe under construction site conditions is a difficult and time consuming task.
Since, for example, two inch outer diameter pipe is wound at approximately 20,000 feet per reel and 31/2 inch outer diameter pipe at 6,000 per reel, use of prewrapped reels of pipe could greatly simplify the pipe laying task. But, while it is clearly desirable to prewrap pipe on a reel, until now no machine has been devised which can accomplish the task. The underlying problem has been that, as pipe is wound onto or unwound from a reel, the diameter of the coil and the alignment of the pipe are constantly varying. Presently known pipe wrap machines are unable to compensate for the resulting variations in speed of pipe travel, much less the combined variation of speed and alignment. For applications in which prewrapped, reeled pipe is required, the pipe is presently wrapped by hand as it is unwound from a feeder reel and rewound on a take-up reel. However, hand wrapping is slow and tedious, typically involving a two feet per minute wrap rate. In most applications, the pipe is wrapped with at least two different materials which, in the hand wrapping process, requires two different wrapping steps. The total time for wrapping a reel of pipe using the hand method is, therefore, generally prohibitive.
It is, therefore, an object of this invention to provide a machine which automatically wraps pipe in reel-to-reel fashion. Similarly, it is an object of this invention to provide a machine which facilitates simultaneous multiple wrapping of pipe in reel-to-reel fashion.